Chapter 4

Which of the following represents a case in which you are not accelerating

Driving in a straight line at 60 miles per hour

Suppose you drop a 10 pound weight and a 5 pound weight on the Moon, both from the same height at the same time. What will happen?

Both will hit the ground at the same time

Why are astronauts weightless in the Space station

Because the space station is constantly in free-fall around the Earth

A net force acting on an object will always cause a change in the object's

momentum

Suppose you are in an elevator that is traveling upward at constant speed. How does your weight compare to your normal weight on the ground?

It is the same

The planets never travel in a straight line as they orbit the Sun. According to Newton's second law of motion, this must mean that

a force is acting on the planets

Suppose the Sun were suddenly to shrink in size but that its mass remained the same. According to the law of conservation of angular momentum, what would happen?

The Sun would rotate faster than it does now

Suppose you kick a soccer ball straight up to a height of 10m. Which of the following is true about the gravitational potential energy of a ball during its flight

The ball's gravitational potential energy is greatest at the instant when the ball is at its highest point

Suppose you heat an oven to 200°C (about 400°F) and boil a pot of water. Which of the following explains why you would be burned by sticking your hand briefly in the pot but not by sticking your hand briefly in the oven?

The water can transfer heat to your arm more quickly than the air

Which of the following scenarios involves energy that we would typically calculate with Einstein's formula?

A small amount of hydrogen in of a nuclear bomb becomes energy as fusion converts the hydrogen to helium

A rock held above the ground has potential energy. AS the rock falls, this potential energy is converted to kinetic energy. Finally, the rock hits the ground and stays there. What has happened to the energy?

The energy goes to producing sound and to heating the ground, rock, and surrounding air

Suppose that the Sun shrank in size but that its mass remained the same. What would happen to the orbit of the Earth?

Earth's orbit would be unaffected

Imagine another solar system, with a star of the same mass as the Sun. Suppose a planet with a mass twice that of Earth (2MEarth) orbits at a distance of 1 AU from the star. What is the orbital period of this planet?

1 year

Imagine another solar system, with a star more massive than the Sun. Suppose a planet with the same mass as Earth orbits at a distance of 1 AU from the star. How would the planet's year (orbital period) compare to Earth's year?

The planet's year would be shorter than Earth's.

Newton showed that Kepler's laws are _________.

natural consequences of the law of universal gravitation

Each of the following lists two facts. Which pair of facts can be used with Newton's version of Kepler's third law to determine the mass of the Sun?

Earth is 150 million km from the Sun and orbits the Sun in one year.

When space probe Voyager 2 passed by Saturn, its speed increased. What must have happened?

Saturn must have lost a very tiny bit of its orbital energy

Suppose that a lone asteroid happens to be passing Jupiter on an unbound orbit. Which of the following statements would be true?

The asteroid's orbit around Jupiter would not change, and it would go out on the same unbound orbit that it came in on

Which of the following best describes the origin of ocean tides on Earth?

Tides are caused by the difference in the force of gravity exerted by the Moon across the Sphere of the Earth

At which lunar phases are tides most pronounced

Both new and full moons

Which of the following best explains why the Moon's orbital period and rotation period are the same?

The moon once rotated faster, but tidal friction slowed the rotation period until it matched the orbital period

Suppose the Moon's orbit were unchanged, but it rotated faster (no synchronous rotation). Which of the following would be true?

We would no longer always see nearly the same face of the moon

The difference between speed and velocity is that

velocity also includes a direction

The acceleration of gravity on Earth is approximately 10 m/s2 (more precisely, 9.8 m/s2). If you drop a rock from a tall building, about how fast will it be falling after 3 seconds?

30 m/s

Momentum is defined as

mass multiplied by velocty

Suppose you lived on the Moon. Which of the following would be true?

Your weight would be less than your weight on Earth, but your mass would be the same as it is on Earth

In which of the following cases would you feel weightless?

While falling from a roof

Which of the following statements is not one of Newton's Laws of Motion

What goes up must come down

Newton's Second Law of Motion tells us that the net force applied to an object equals its

mass multiplied by acceleration

Suppose that two objects collide. Which of the following things is not the same both before and after the collision

the total temperature of the objects

When a spinning ice skater pulls in his arms, he spins faster because

his angular momentum must be conserved, so reducing his radius must increase his speed of rotation

The energy attributed to an object by virtue of its motion is known as

kinetic energy

Radiative energy is

energy carried by light

Absolute zero is

0 Kelvin

What does the term temperature measure?

The average kinetic energy of particles in a substance

In the formula E = mc2, what does E represent?

The mass-energy, potential energy stored in an object's mass

What is the difference between a bound orbit and an unbound orbit around the Sun?

An object on a bound orbit follows the same path around the Sun over and over, whereas an object on an unbound orbit approaches the Sun just once and then never returns

The allowed shapes for the orbits of objects responding only to the force of gravity are